In patent application Ser. No. 12/183,527, filed Jul. 31, 2008 (TRANSVI.024A), there is described a modular hemofiltration apparatus with removable panels for multiple and alternate blood therapy. In use of the apparatus, one or more fluid holding bags are secured to the control unit for receiving waste fluid separated from a patient's blood by a hemofilter, as well as one or more fluid holding bags which contain fluids to be directed to the fluid pumping apparatus for supplying saline, anticoagulant, replacement fluids, and dialysate fluid. The aforesaid application is incorporated herein by reference in its entirety.
Hemofiltration apparatus used and known heretofore, incorporate weight sensors or load sensors to which each fluid holding bag is connected. Each load sensor is operatively connected to the control unit for signaling the weight of each bag and informing an operator of the bag weight. The bag weight may be displayed on a screen for observation by the operator for monitoring the continuing increase or decrease of weight or volume for each bag receiving or supplying the fluid. A bag hanger, typically having one or more hooks on which the fluid holding bag is secured, hangs directly from the load sensor by a hook or similar component. Although at any instant, the correct load or weight of a bag may be sensed by the load cell sensor, as a therapy session proceeds, any contact of a bag with an adjacent bag, person or other apparatus at least temporarily interrupts the linear weight change slope resulting in inaccurate load sensing and readings. Moreover, if a fluid holding bag is initially hung on a bag holder rack or hook assembly, somewhat askew, off-center or crooked, as a bag is emptied and loses weight, uneven or non-linear weight readings may result.